<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <script>
    let arr1=[1,2,3];
    let arr2=[5,6,7];

    let arr=[...arr1, ...arr2];

    alert(arr);
    </script>
  </head>
  <body>

  </body>
</html>
